1. Field of the Invention
The present invention relates to a motor, and more particularly to a technology used to connect a bus wire of an armature of a motor to an external power source.
2. Description of the Related Art
A motor typically includes an armature having a plurality of coils arranged in an annular shape via which a multiple phase alternating current is supplied. There are many methods used to prevent coils of different phases from making contact with one another inside the armature. For example, Japanese Laid-Open Patent Publication (S) 61-227648 discloses an armature which includes two groove portions having an annular shape arranged at an upper surface and a lower surface of an insulating layer which cover a yoke portion of an annular shape, wherein lead wires of each phase are accommodated in different groove portions so as to avoid the contact among the lead wires.
In an armature disclosed in Japanese Laid-Open Patent Publication (H) 10-4645, an upper cover and a lower cover which cover a stator core of an annular shape include an indent portion having an annular shape in which lead wires of each phase are aligned so as to insulate them.
According to Japanese Laid-Open Patent Publication 2000-134844, an armature includes a plurality of wire containing portions having a groove shape for accommodating therein lead wires of each phase and arranged at an outer side surface of an insulator to cover a core in a direction parallel with the central axis of the core.
On the other hand, in a conventional armature that does not rely on lead wires, a busbar is used to connect a bus wire of the armature and an external power source. For example, in a busbar as disclosed in a Japanese Laid-Open Patent Publication 2003-284279, a plurality of laminated ring bodies are each insulated from one another, wherein each ring body includes an external connection terminal at an outer side thereof and a coil connection terminal at an inner side thereof.
In recent years, the number of coils used in a motor has increased in order to improve the performance of the motor while the dimensions of the motor are expected to be reduced. Also, a position sensor used in a motor to detect a rotation of the motor is arranged around the armature which further complicates the wiring of the lead wires forming the coils while a space used for the wiring is minimized. Therefore, according to a method in which a busbar is used to connect the bus wire from the armature to an external power source, it is difficult to reduce the dimensions of the motor while manufacturing efficiency and accuracy are compromised.